Electron discharge tube and the like



Feb. 6, 1940.

M. A. ACHESON ET AL ,250

ELECTRON DISCHARGE TUBE AND THE LIKE Filed Jan. 15, 1939 INVENTORS ATTORN EY Patented Fea 1940 UNITED STATES PATENT OFFICE Marcus A. Acheson and Raymond McClintock, Emporium, Pa... assignors to Hygrade Sylvania Corporation, Salem, Mass., a corporation of Massachusetts Application January 13, 1939, Serial No. 250,684

7 Claims.

This invention is concerned with electron dischar e tubes, and more especially with mount assemblies and supports for such devices as radio tubes and the like.

A principal object of the invention is to provide an improved mount assembly for tubes especially designed for high frequency work.

Another object is to provide an improved mount assembly which is compact and rigid in construction.

A feature of the invention relates to a tube wherein the mount is provided with a plurality of contact prongs so positioned with respect to the electrode assembly as to facilitate welding the connecting wires or metal straps between the prongs and electrodes.

Another feature is to provide a tube particularly suitable for high frequency work, wherein the overall dimensions of the tube are reduced to a minimum.

A further feature relates to the novel organization, arrangement and relative location of partsf'which constitute an improved radio tube of small dimensions.

Other features and advantages not specifically enumerated will be apparent after a consideration of the following detailed descriptions and the appended claims. While the invention finds its greatest utility in tubes of the flattened glass header type, in certain of its aspects it is capable of application to other types of tubes, for example those of the so-called metal header type, and indeed in any tube wherein the lead-in wires are disposed around a common center. In the drawin Fig. 1 is a perspective view, partly sectional, of a radio tube embodying features of the invention.

Fig. 2 is a top plan view of Fig. 1 with the top of the bulb removed.

Referring to the drawing the tube comprises an enclosing envelope consisting of a glass bulb portion I sealed to a cup-like glass portion 2 having a substantially flat bottom or header 3 and a rim 4. Preferably, although not necessarily, the bottom 3 is of relatively thick glass and the thickness of rim tapers down to the region 5 where it is sealed to the bulb I.

Sealed through the header 3 are the rigid metal rods 6 to i3, and preferably the header is provided with integral raised beads I4 in the regions where the rods are sealed therethrough. In accordance with the invention the rods 6 to l3 are arranged in a circle about the center of header 3, and the latter may have at its center an exhaust opening, closed oil by a sealed-off downwardly depending exhaust tubulation. Thus the entire enclosing envelope is of glass and the contact prongs 6 to It are directly sealed therethrough. 5

The envelope with its contact prongs may be seated within a cup-shaped metal base I5 having a flat bottom l6 and a rim l1 which may be fastened to the envelope in any suitable manner, for example by a ring of cement ll. It will be 10 understood of course that the bottom It is provided with a series of circularly arranged openings through which the prongs 6 to 13 respectively pass, and preferably the under surface of header 3 is provided with beads (not shown) similar to beads H, which fit snugly in the openings in bottom Hi to insulate the several prongs from base l5. Preferably also, the basel5 has centrally attached thereto or formed integrally therewith, a hollow downwardly depending metal 20 boss l8 having a keying rib IS on one side to cooperate with a corresponding keyway in any wellknown form of socket into which the tube is to be plugged, it being understood that the prongs 6 to l3 likewise are plugged into the correspond- 26 ing contacts in the socket. The member l8 being hollow encloses and protects the downwardly depending exhaust tubulation (not shown) and if desired, the base l5 and member l8 may be grounded or connected to a suitable potential 80 source whereby said base and member l8 act as an electrostatic shield between certain of the contact prongs, for example the control grid prong l3 and plate prong 8. For a more detailed description of a bulb and base of this type, ref- 85 erence may be had to application Serial No. 189,295, filed February 8, 1938.

In accordancewith the present invention, the rods 6 to I3 are extended upwardly the full length of the electrode assembly so that said as- 4,0 sembly is surrounded by said prongs. Merely for purposes of explanation, the electrode assembly is shown as of the pentode type, comprising a central electron emitting cathode sleeve 20, a control grid 2|, a shield grid 22, a suppressor 5 grid 23, and a plate electrode 24. The heater filament of any wellknown type is insulatingly supported within sleeve 20 and the free ends 25, 26, are, in accordance with the invention, brought out through the upper end of sleeve 20.

The grid electrodes and the plate electrode are provided with the usual side rod supports. Thus the control grid has side rods 21, 28; the shield grid, side rods 29, 30; the suppressor grid, side rods 3|, 32; the plate, side rods 33, 34. The

various electrodes may be mounted between upper and lower insulator spacer members 35, 36, in the form of mica discs having series of aligned perforations to receive the ends of the various side rods. Discs 35, 36, may be held in place on the side rods in any wellknown manner, for example by peening the side rods adjacent the discs, or by pro v,iding the discs with one or more metal eyelets' through which the side rods pass. The electrode assembly is therefore of the socalled unitary type and can be assembled as a unit on the header 3.

In order to position the electrode assembly accurately on the header and to prevent it shifting laterally,the edges of discs 35, 36, are provided with semi-circular notches, there being one notch on each disc for each of the rods 6 to l3, and in which the respective rods fit snugly. If desired, the discs 35, 36, instead of having their'edges notched, may be perforated to fit over the rods 6 to I3, although the notch arrangement facilitates welding as will be described.

As shown, the electrode assembly rests at its lower end on beads l4 and the rods 6 to I 3 extend upwardly a short distance beyond the disc 35. By this arrangement the electrical connections to all the electrodes can be made at one end of the mount, namely at the upper end. Thus the filament ends 25, 26, can be welded to respective short metal straps 31, 38, which in turn are welded to the filament prongs 6, I I; the oathode sleeve 20 is connected to prong 10 by strap 38; the control grid side rod 21 is connected to its prong l3 by strap 39; shield grid side rod 30 is connected to its prong I by strap 40; suppressor grid side rod 32 is connected to its prong 9 by strap 4|; and plate side rod 34 is connected to its prong 8 by strap 42.

40 The above-describedarrangement in addition to facilitating the welding of the various side rods connecting straps and thus enabling the connections to be made on automatic machinery, has the advantage of reducing the undesirable electrostatic coupling between the various leadin connections to a minimum. Heretofore the filament ends. have brought out at the lower end of the mount, necessitating a relatively difficult or inconvenient welding arrangement, particularly where the lower end of the mount is very close to the header 3. It will be understood of course that the mount may be held against vertical movement by peening the upper end of one or more of the rods 6 to I3, adjacent the upper face of disc 35, or in any other way wellknown in the radio tube art. Various changes and modifications may be made in the type of electrode assembly without departing from the spirit and scope of the invention. Thus instead of having the mount rest at its lower end on beads I, it may be supported above the header 3 any desired distance, for example, by projections or enlargements on the rods 6 to I3. If desired, the part of control grid prong l3 which is within the envelope may be surrounded or enclosed within a metal shield spaced therefrom, which shield may be grounded to reduce the electrostatic coupling as disclosed in said application Serial No. 189,295, filed February 8, 1938.

What we claim is:

1. An electron discharge tube mount comprising a header, a plurality of metal rods carried by said header, an electrode assembly surrounded by said rods, said rods extending upwardly to the upper end of said assembly, and connections from the upper ends of said electrodes to the upper ends of said rods.

2. An electron discharge tube mount comprising a header, a plurality of metal rods carried by said header around a common center, an electrode assembly surrounded by said rods and including a filament the ends of which are brought out at the upper end of said mount, and connections from said filament ends to corresponding ones of said rods.

3. An electron discharge tube mount comprising a header, a plurality of vertical metal rods carried by said header around the center thereof, an electrode assembly including a filament and at least one surrounding electrode having a side rod, and a strap connecting the upper end of said filament and the upper end of one of said vertical rods, and another strap connecting the upper end of said side rod and the upper end 7 of another one of said vertical rods.

4. An electron discharge tube mount comprising a header, a plurality of rigid metal contact prongs sealed through said header, an electrode assembly supported from said header, said prongs extending upwardly to the upper end of said assembly, electrodes to the upper ends of said rods above said assembly.

5. An electron discharge tube mount comprising a header, a plurality of rigid metal rods carried by said header and arranged in a circle around the center thereof, an electrode assembly including a plate electrode with upper and lower spacer members extending outwardly beyond said plate, said spacer members having a plurality of openings in the peripheral margins one for each of said rods, said assembly being positioned with said rods in said openings.

6. A mount according to claim in which said assembly is of the unitary type and the lower spacer member rests on said header.

7. An electron discharge tube comprising an enclosing envelope closed oil at its lower end by a circular header, a plurality of rigid metal contact prongs sealed through said header said header having beads around each prong at the seal-in region, an electrode assembly having an insulator spacer at its lower end resting upon said beads, and connections from the upper ends of the electrodes of the assembly to the upper ends of said prongs.

MARCUS A. ACHESON. RAYMOND MCCLINTOCK.

and electrical connections from said 

